Extinguishing a Point of Contention: Examining Transboundary Haze in Southeast Asia

As Indonesia faces another year of intensifying peatland fires, longstanding regional tensions around transboundary haze continue to envelop Southeast Asia. Neighboring Malaysia is concerned about the haze’s severity this year, urging joint regional action against rising air pollution levels. Malaysia’s vocal stance on the issue raises the question, “Will the Association of Southeast Asian Nations (ASEAN) be able to generate an updated regional response to the rising issue of transboundary haze in Southeast Asia?” To consider an updated agreement, ASEAN policymakers must reexamine past joint efforts, such as the 1997 Regional Haze Action Plan (RHAP) and the 2002 ASEAN Agreement on Transboundary Haze (AATHP) and consider implementing domestic transboundary haze legislation to encourage accountability and haze prevention.

Transboundary haze has been a recurring point of contention in Southeast Asia for over 50 years, with initial cases reported as early as 1972. Indonesia and Malaysia’s peatland fires contribute to the majority of transboundary haze, most notably due to slash-and-burn techniques in Sumatra and the Kalimantan region of Borneo Island. In 1997, ASEAN faced one of the most severe cases of transboundary haze, when fires from both Sumatra and Kalimantan caused haze to reach Malaysia, Singapore, Brunei, Thailand, and the Philippines, even reaching westward toward Sri Lanka. The haze not only caused an increased demand for air-quality-related health care, but also caused major disruptions in air and business travel, causing $9 billion in damages. In response, ASEAN adopted the 1997 RHAP, detailing urgent action in monitoring, preventing, and mitigating the haze. Though not legally binding, RHAP was a turning point in ASEAN’s regional approach to transboundary haze, creating a concrete action plan meant to tackle the issue at its roots. Future preventative measures included the establishment of a Haze Technical Task Force that would meet monthly and review progress on RHAP implementation, as well as regular meetings among the ASEAN environment ministers to provide guidance.

Five years later, ASEAN implemented its first legally binding measure against transboundary haze, the 2002 AATHP. Officially entering into force in 2003, the agreement formally recognizes haze as an ASEAN issue, encouraging regional cooperation. The agreement is very comprehensive, consisting of an ASEAN Taskforce on Peatlands, as well as a joint ASEAN Haze Fund to support relevant activities to implement the AATHP and emergency use. Notably, Indonesia was the final country to join the agreement, not signing until October 2014, almost a decade after most of its ASEAN counterparts.

After three years of reduced haze due to regional Covid-19 precautions, transboundary haze spiked again in 2023, driven by the El Niño weather phenomenon, impacting Indonesia, Malaysia, and Singapore. Malaysia was especially vocal about the haze this year, with Malaysian minister of natural resources, environment, and climate change Nik Nazmi submitting a letter to his Indonesian counterpart, “urging them to take action on the matter.” In contrast, Indonesian officials pushed back against Malaysia’s haze accusations, declaring that they had not detected any haze outside of their borders. Despite finger pointing between Putrajaya and Jakarta, Malaysia still recorded an unhealthy Air Pollution Index (API) of 158 in late September, while Indonesia reported an API of over 300 in South Sumatra. Dangerous air levels led the countries to consider mandating online classes for students, as well as issuing health advisory notices. The haze’s strong emergence increased regional tensions. While the AATHP and RHAP reflected joint regional action, as well as a unified response to severe haze episodes, they did not solve the clear political tensions throughout the region. ASEAN nations must enact domestic transboundary haze pollution laws in order to hold one another, as well as themselves, accountable, putting a rest to the great ASEAN haze blame game.

Mainland Southeast Asia faces its own set of challenges from November to February, with slash-and-burn farming creating haze-catalyzing fires from Thailand, Laos, and Myanmar. Thailand has been particularly vocal about this issue, coordinating with Laos and Myanmar to reduce fires around their boarders to mitigate the haze. But with November here the haze will continue to burden Mainland Southeast Asia until concrete action plans are finalized.

Below are three different ASEAN countries, each impacted by transboundary haze but having taken very different approaches to domestic legislation on the issue. Each country faced different challenges in successfully implementing domestic haze legislation, contributing to ongoing regional tensions. 


With Singapore’s thorough climate ambitions, they lead by example as the first and only ASEAN country to enact a domestic transboundary haze regulation. In 2014, Singapore enacted the Transboundary Haze Pollution Act, which creates extra-territorial liability for anything that causes or contributes to haze pollution in the country. If satellite or other meteorological evidence displays indicate that there is any land fire moving toward Singapore, the nation presumes there is haze pollution in Singapore. However, National University of Singapore academics have criticized the act, noting that while it is airtight, successful prosecution of offending companies or national bodies will not necessarily solve the problem at hand. Proper resolution ultimately comes down to Indonesian enforcement and prosecution, one of the main contributors to the majority of Southeast Asia’s transboundary haze.


While Indonesia has not explicitly passed any laws relating to transboundary haze, it enacted regulations that prohibit primary haze-causing catalysts. Forestry Law (No. 41, 1999) details that intentionally setting off fires can lead to 15 years imprisonment as well as a fine of $450,000. Management of the Environment Law (No. 32, 2009) outlines a legal framework for entities to manage business-caused impacts on the environment. This law sentences 3-10 years imprisonment and a fine of $260,000 - $900,000 to violators. A study by the National University of Singapore highlights inconsistencies in law enforcement: most cases brought under the Forestry Law or Management of the Environment Law end in acquittals, reversal of convictions upon appeal, or lesser punishments than detailed. As a result, while Indonesia has created laws to attempt to prevent haze, the country still lacks effective enforcement of these laws, undermining their significance. For Indonesia to effectively implement domestic transboundary haze legislation, it must reexamine the means of enforcement and domestic accountability.


Though aspiring to push back against transboundary haze in Southeast Asia, Malaysia’s unstable politics has prevented it from enacting any domestic transboundary haze laws. In 2018, the Pakatan Harapan government drafted a Transboundary Haze Pollution Act. However, once Perikatan Nasional took office in 2020, they tabled the act in favor of “a more regional approach.” Malaysian academics consider the dropped law to be a missed opportunity to take accountability for the country’s share of transboundary haze in the region. Another notable limitation was the scope of the drafted law, which intended to hold only domestic firms accountable. This stands in contrast to Singapore’s Transboundary Haze Pollution Act, which targets any entity accountable for haze. If Malaysia were to establish a domestic transboundary haze law similar to that of Singapore’s, it would have an immediate legislative advantage against Indonesia by showcasing that  Malaysia is taking responsibility forits portion of transboundary haze and keeping local firms accountable, while monitoring transboundary haze from external sources. A comprehensive domestic law will neutralize the blame game, allowing Malaysia to lead by example and encourage neighbors like Indonesia to do the same.  

By establishing airtight domestic legislation against transboundary haze, ASEAN countries would not only hold domestic actors accountable, but also enhance their existing joint regional agreements and action plans. If all ASEAN nations adopted such legislation, it would prevent finger pointing during future transboundary haze episodes. Such regulations may also prevent catalysts that could worsen transboundary haze in the future, extinguishing not only peatland fires but also political tensions.

Lauren Mai is a program coordinator and research assistant for the Southeast Asia Program at the Center for Strategic and International Studies in Washington, D.C.

Lauren Mai
Program Coordinator and Research Assistant, Southeast Asia Program